Liquid crystal display and method of manufacturing the same

ABSTRACT

A liquid crystal display includes a first substrate including pixels, each having a transmissive area and a reflective area, a second substrate, and a liquid crystal layer disposed between the first and second substrates. Each of the pixels includes first and second thin film transistors which output a data signal in response to a first gate signal, a transmissive pixel electrode disposed in the transmissive area and electrically connected to the first thin film transistor to charge a first pixel voltage based on the data signal, a reflective pixel electrode disposed in the reflective area and electrically connected to the second thin film transistor to charge a second pixel voltage based on the data signal, and a voltage controller which controls the first pixel voltage and the second pixel voltage in response to a second gate signal, which is generated after the first gate signal.

This is a divisional of a Continuation-in-Part of application Ser. No.12/814,870, filed on Jun. 10, 2010 which claims priority to U.S.non-provisional patent application claims priority under 35 U.S.C. §119of Korean Patent Application No. 10-2010-0028236 filed on Mar. 30, 2010,and is a Continuation-in-Part of application Ser. No. 12/620,801 filedon Nov. 18, 2009 which claims priority to Korean Patent Application No.10-2009-0059233, filed on Jun. 30, 2009, all of which are incorporatedby reference as if set forth fully herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display and a methodof manufacturing the liquid crystal display. More particularly, thepresent invention relates to a transflective liquid crystal displayhaving a single cell gap and a method of manufacturing the liquidcrystal display.

2. Description of the Related Art

A liquid crystal display (“LCD”) typically includes a liquid crystallayer disposed between two transparent substrates. To display a desiredimage, the LCD drives the liquid crystal layer to control atransmittance of light for each pixel.

In general, an LCD is classified as either a transmissive LCD, whichdisplays an image using a backlight unit as a light source thereof, or areflective LCD, which displays an image using natural light as a lightsource thereof, e.g., without requiring a backlight unit.

Compared to the reflective LCD, the transmissive LCD, which requires thebacklight unit, has a high power consumption. Although it does notrequire a backlight, and thus consumes less power, the reflective LCDcannot display an image if there is insufficient ambient light.

In attempts to overcome the abovementioned problems with transmissiveand reflective LCDs, a transflective LCD, which has both a reflectivearea and a transmissive area, has recently been suggested. Since thetransflective LCD operates in both reflective and transmissive modes,depending on the environment or surroundings of the LCD, thetransflective LCD has relatively low power consumption, and is also ableto be used in places with low ambient light.

However, the transflective LCD typically has a single cell gap structureand, as a result, a gray-scale difference occurs in the reflective andtransmissive areas due to a phase retardation difference therein,thereby causing deterioration of display quality of the LCD. Incontrast, when the transflective LCD has a dual cell gap structure, inwhich a cell gap of the transmissive area is larger than a cell gap ofthe reflective area, a step difference occurs between the reflective andtransmissive areas. As a result, it is difficult to control a liquidcrystal director, due to the step difference, and defects in patterningoccur in a manufacturing process, thereby causing deterioration of boththe display quality and production efficiency of the LCD.

Accordingly, it is desired to develop a transflective LCD that overcomesat least the problems discussed above.

BRIEF SUMMARY OF THE INVENTION

An exemplary embodiment of the present invention provides atransflective liquid crystal display (“LCD”) having a single cell gapstructure and substantially improved display quality.

Another exemplary embodiment of the present invention provides a methodof manufacturing the transflective LCD.

In an exemplary embodiment of the present invention, a liquid crystaldisplay includes a first substrate including a plurality of pixels, eachof which has a transmissive area and a reflective area, a secondsubstrate opposite to the first substrate, and a liquid crystal layerdisposed between the first substrate and the second substrate.

Each pixel includes a first thin film transistor and a second thin filmtransistor, a transmissive pixel electrode, a reflective pixel electrodeand a voltage controller. The first and second thin film transistorsoutput a data signal in response to a first gate signal. Thetransmissive pixel electrode is disposed in the transmissive area and iselectrically connected to the first thin film transistor to charge afirst pixel voltage based on the data signal. The reflective pixelelectrode is disposed in the reflective area and is electricallyconnected to the second thin film transistor to charge a second pixelvoltage based on the data signal. The voltage controller controls thefirst and second pixel voltages in response to a second gate signalgenerated after the first gate signal.

The transmissive area has a cell gap that is equal to or larger than acell gap of the reflective area.

According to an exemplary embodiment, each pixel further comprises afirst gate line which receives the first gate signal, a second gate linewhich receives the second gate signal, and a data line which receivesthe data signal.

The voltage controller includes a third thin film transistor, a chargedividing electrode and a storage line. The third thin film transistorincludes a source electrode connected to a drain electrode of the secondthin film transistor and outputs a voltage control signal in response tothe second gate signal. The charge dividing electrode is connected to adrain electrode of the third thin film transistor and is charged withthe voltage control signal. The storage line overlaps at least a portionof the charge dividing electrode to form a first capacitor whichcontrols the first pixel voltage and the second pixel voltage.

The first gate line is connected to a first pixel of the pixels, thesecond gate line is connected to a second pixel, adjacent to the firstpixel, of the pixels, and the voltage controller receives the secondgate signal through the second gate line.

The voltage controller may include: a third thin film transistorincluding a source electrode connected to the reflective pixel electrodeand which outputs a voltage control signal in response to the secondgate signal; a charge dividing electrode connected to a drain electrodeof the third thin film transistor and which is charged with the voltagecontrol signal; and a storage line which overlaps at least a portion ofthe charge dividing electrode to form a first capacitor which controlsthe first pixel voltage and the second pixel voltage.

The second substrate may include: a color filter layer; and atransparent organic layer disposed in a first area of the color filterlayer such that a thickness of the first area is less than a thicknessof a second area, different from the first area, of the color filterlayer.

The second substrate may include a color filter layer, and the colorfilter layer may include at least one penetrating hole formedtherethrough at an area corresponding to the reflective area of acorresponding pixel of the pixels.

A cell gap of the area at which the penetrating hole is formed isgreater than a cell gap of another area of the color filter layer.

The second substrate may include: a common electrode which forms anelectric field with the transmissive pixel electrode and the reflectivepixel electrode; and at least one dividing pattern disposed on at leastone of the transmissive pixel electrode, the reflective pixel area andthe common electrode. The at least one dividing pattern divides theliquid crystal layer into domains.

The reflective pixel electrode may include a concavo-convex portion.

The domains have different areas.

The liquid crystal display may further include: a first polarizerdisposed on an outer surface of the first substrate; a second polarizerdisposed on an outer surface of the second substrate; and at least onephase retardation film disposed at least one of between the firstsubstrate and the first polarizer and between the second substrate andthe second polarizer.

At least one of the first polarizer, the second polarizer and the atleast one phase retardation film may include an anti-glare portiondisposed thereon.

In another exemplary embodiment, a method of manufacturing a liquidcrystal display is provided, the method including: forming a firstsubstrate comprising pixels, each of which includes a transmissive areaand a reflective area; forming a second substrate opposite to the firstsubstrate; and forming a liquid crystal layer between the firstsubstrate and the second substrate.

The forming the first substrate includes: forming a first thin filmtransistor, a second thin film transistor, and a third thin filmtransistor on a first insulating substrate disposed on the firstsubstrate; forming a transmissive pixel electrode, connected to thefirst thin film transistor, in the transmissive area and; forming areflective pixel electrode, connected to the second thin filmtransistor, in the reflective area; and forming a voltage controlleroverlapping at least a portion of the transmissive pixel electrode.

A cell gap of the transmissive area is greater than or equal to a cellgap of the reflective area.

The forming the first thin film transistor, the second thin filmtransistor and the third thin film transistor may include: forming afirst gate line and a second gate line on the first substrate; forming adata line which crosses the first gate line and the second gate line onthe first substrate; interposing a gate insulating layer between thedata line and each of the first gate line and the second gate line;forming the first thin film transistor and the second thin filmtransistor connected to the first gate line and the data line,respectively; and forming the third thin film transistor connected to adrain electrode of the second thin film transistor and the second gateline.

The forming the voltage controller includes: forming a storage line,spaced apart from and insulated from the first gate line and the secondgate line, on the first substrate; forming a charge dividing electrode,connected to the third thin film transistor and which overlaps at leasta portion the storage line, on the first substrate; and interposing thegate insulating layer between the charge dividing electrode and thestorage line.

The charge dividing electrode overlaps at least a portion of thetransmissive pixel electrode, and a protective layer is interposedbetween the charge dividing electrode and the at least a portion of thetransmissive pixel electrode. The preparing the second substrate mayinclude: forming a common electrode, configured to form an electricfield with the transmissive pixel electrode and the reflective pixelelectrode, on a second insulating layer; and forming at least onedividing pattern in the common electrode. The forming the firstsubstrate may further include forming at least one dividing pattern inat least one of the transmissive pixel electrode and the reflectivepixel electrode.

The forming the first thin film transistor, the second thin filmtransistor and the third thin film transistor may include: forming afirst gate line and a second gate line on the first substrate; forming adata line which crosses the first gate line and the second gate line onthe first substrate; interposing a gate insulating layer between thedata line and both the first gate line and the second gate line; andconnecting the first thin film transistor and the second thin filmtransistor to the first gate line and the data line; and connecting thethird thin film transistor to the transmissive pixel electrode and thesecond gate line.

The forming the voltage controller includes: comprises forming a storageline, spaced apart from and insulated from the first gate line and thesecond gate line, on the first substrate; forming a charge dividingelectrode, connected to the third thin film transistor and whichoverlaps at least a portion of the storage line, on the first substrate;and interposing the gate insulating layer between the charge dividingelectrode and the storage line.

The charge dividing electrode overlaps at least a portion of thetransmissive pixel electrode, and a protective layer is interposedbetween the charge dividing electrode and the at least a portion of thetransmissive pixel electrode.

The forming the second substrate includes: forming a common electrode,configured to form an electric field with the transmissive pixelelectrode and the reflective pixel electrode, on a second insulatinglayer; and forming at least one dividing pattern in the commonelectrode. The forming the first substrate may further include formingat least one dividing pattern in at least one of the transmissive pixelelectrode and the reflective pixel electrode.

In yet another exemplary embodiment, a liquid crystal display includes:a first substrate comprising pixels, each of which includes atransmissive area and a reflective area; a second substrate facing thefirst substrate; and a liquid crystal layer disposed between the firstsubstrate and the second substrate.

Each pixel includes: a first thin film transistor which outputs a firstdata signal in response to a gate signal; a second thin film transistorwhich outputs a second data signal in response to the gate signal; atransmissive pixel electrode disposed in the transmissive area andconnected to the first thin film transistor, and which charges a firstpixel voltage in response to the first data signal; and a reflectivepixel electrode disposed in the reflective area and connected to thesecond thin film transistor and which charges a second pixel voltage inresponse to the second data signal.

The second substrate includes: a common electrode which forms anelectric field with the transmissive pixel electrode and the reflectivepixel electrode; and at least one dividing pattern disposed on at leastone of the transmissive pixel electrode, the reflective pixel electrodeand the common electrode to divide the liquid crystal layer intodomains.

A cell gap of the transmissive area is greater than or equal to a cellgap of the reflective area.

The liquid crystal display may further include: a first sub-thin filmtransistor which outputs a first sub-data signal in response to the gatesignal; and a voltage controller connected to the first sub-thin filmtransistor.

The transmissive pixel electrode includes: a first transmissive pixelelectrode connected to a drain electrode of the first thin filmtransistor to charge a first transmissive pixel voltage; and a secondtransmissive pixel electrode spaced apart from the first transmissivepixel electrode and connected to the first sub-thin film transistor tocharge a second transmissive pixel voltage. The voltage controllercontrols the first transmissive pixel voltage and the secondtransmissive pixel voltage in response to a next gate signal of a nextpixel generated after the gate signal.

Thus, according to the exemplary embodiments described herein, a liquidcrystal layer corresponding to a transmissive area is driven by avoltage different from a voltage used to drive a liquid crystal layercorresponding to a reflective area, and a phase retardation value of thereflective area is matched with a phase retardation value of thetransmissive area. Thus, a gray-scale difference between thetransmissive area and the reflective area is substantially reduced anddeterioration of electro-optical characteristic of the liquid crystallayer is effectively prevented, thereby greatly improving a displayquality of the liquid crystal display. In addition, the liquid crystaldisplay according to an exemplary embodiment has a signal cell gap, andthus does not require the same patterning processes used to manufacturea liquid crystal display having a dual cell gap. As a result, amanufacturing process for the liquid crystal display is simplified, andmanufacturing process defects are substantially reduced and/oreffectively prevented.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the present invention willbecome more readily apparent by describing in further detail exemplaryembodiments thereof with reference to the accompanying drawings, inwhich:

FIG. 1 is a plan view of an exemplary embodiment of a liquid crystaldisplay (“LCD”) according to the present invention;

FIG. 2 is a partial cross-sectional view taken along line A-A′ of FIG.1;

FIG. 3 is an equivalent circuit diagram of a pixel of the liquid crystaldisplay of FIG. 1;

FIG. 4 is an equivalent circuit diagram of an n-th pixel when a gatesignal is applied to an n-th gate line of the pixel of FIG. 3;

FIG. 5 is a graph of reflection and transmission versus applied voltageillustrating an exemplary embodiment of a method of controlling a lighttransmission amount and a light reflection amount in the liquid crystaldisplay of FIG. 1;

FIG. 6 is a partial cross-sectional view of another exemplary embodimentof a liquid crystal display according to the present invention;

FIGS. 7A through 7E are plan views of additional exemplary embodimentsof a liquid crystal display according to the present invention;

FIG. 8A is a plan view of one exemplary embodiment of an LCD accordingto the present invention;

FIG. 8B is a partial cross-sectional view taken along line B-B′ of FIG.8A;

FIG. 8C is a partial cross-sectional view taken along line C-C′ of FIG.8A;

FIG. 9A is a graph showing a reflection luminance of a reflective pixelelectrode according to a solar altitude when protrusions are providedwith different pitches;

FIG. 9B is a graph showing a reflection luminance of a reflective pixelelectrode according to a solar altitude when protrusions are providedwith different contact angles;

FIG. 10 is a partial cross-sectional view taken along line B-B′ of FIG.8A according to another exemplary embodiment of the present invention;

FIG. 11 is a graph showing a reflection luminance of a reflective pixelelectrode according to a solar altitude when protrusions are providedwith different pitches;

FIG. 12 is a plan view of yet another exemplary embodiment of a liquidcrystal display according to the present invention;

FIG. 13 is an equivalent circuit diagram of a pixel of the liquidcrystal display of FIG. 12;

FIG. 14 is a plan view of still another exemplary embodiment of a liquidcrystal display according to the present invention; and

FIG. 15 is a plan view of yet an additional exemplary embodiment of aliquid crystal display according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention now will be described more fully hereinafter withreference to the accompanying drawings, in which various embodiments areshown. This invention may, however, be embodied in many different forms,and should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like reference numerals refer tolike elements throughout.

It will be understood that when an element is referred to as being “on”another element, it can be directly on the other element or interveningelements may be present therebetween. In contrast, when an element isreferred to as being “directly on” another element, there are nointervening elements present. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another element, component, region, layer or section. Thus,a first element, component, region, layer or section discussed belowcould be termed a second element, component, region, layer or sectionwithout departing from the teachings of the present invention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. It willbe further understood that the terms “comprises” and/or “comprising,” or“includes” and/or “including” when used in this specification, specifythe presence of stated features, regions, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, regions, integers, steps,operations, elements, components, and/or groups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

Hereinafter, exemplary embodiments of the present invention will bedescribed in further detail with reference to the accompanying drawings.

FIG. 1 is a plan view of an exemplary embodiment of a liquid crystaldisplay (“LCD”) according to the present invention, and FIG. 2 is apartial cross-sectional view taken along line A-A′ of FIG. 1.

Referring to FIGS. 1 and 2, a liquid crystal display includes a firstsubstrate 100, a second substrate 200 disposed opposite to, e.g.,facing, the first substrate 100 and a liquid crystal layer 300 disposedbetween the first substrate 100 and the second substrate 200.

The first substrate 100 includes a first insulating substrate 101including pixels, each of which having a reflective area RA and atransmissive area TA. The first insulating substrate 101 includes N gatelines GL₁, . . . , GL_(n), GL_(n+1), . . . , GL_(N), N sub-gate linesGL₁′, . . . , GL_(n)′, GL_(n+1)′, . . . , GL_(N)′ disposed substantiallyparallel and correspondingly to the N gate lines, and M data lines DL₁,. . . , DL_(m), DL_(m+1), . . . , DL_(M), and each pixel includes onegate line GL of the N gate lines GL₁, . . . , GL_(n), GL_(n+1), . . . ,GL_(N), one sub-gate line GL′ of the N sub-gate lines GL₁′, . . . ,GL_(n)′, GL_(n+1)′, . . . , GL_(N)′, and one data line DL of the M datalines DL₁, . . . , DL_(m), DL_(m+1), . . . , DL_(M). Hereinafter, forpurposes of explanation, one pixel having an n-th gate line GL_(n), ann-th sub-gate line GL_(n)′ and an m-th data line DL_(m) will bedescribed in further detail in conjunction with an (m+1)th data lineDL_(m+1), as shown in FIG. 1, but it will be noted that alternativeexemplary embodiments are not limited. In an exemplary embodiment, eachpixel has substantially the same structure and function as the otherpixels in the LCD.

Referring to FIGS. 1 and 2, on the first substrate 100, the pixelincludes the n-th gate line GL_(n), the n-th sub-gate line GL_(n)′, afirst gate electrode GE1 the n-th gate line GL_(n), and a storage lineCST disposed on the first insulating substrate 101.

The first insulating substrate 101 is formed of a transparent material,such as glass, for example. The n-th gate line GL_(n) is disposed on thefirst insulating substrate 101 and extends along a first direction(e.g., along a horizontal or row direction, as viewed in FIG. 1). Then-th sub-gate line GL_(n)′ is disposed substantially parallel to then-th gate line GL_(n) and is spaced apart from the n-th gate lineGL_(n). The first gate electrode GE1 may branch from the n-th gate lineGL_(n) along a second direction, e.g., a horizontal or column direction(as viewed in FIG. 1) substantially perpendicular to the firstdirection. However, in an exemplary embodiment, the first gate electrodeGE1 is disposed on at least a portion of the n-th gate line GL_(n). Thestorage line CST is spaced apart from the n-th gate line GL_(n) and then-th sub-gate line GL_(n)′ and is disposed substantially parallel to then-th gate line GL_(n) and the n-th sub-gate line GL_(n)′. In addition, aportion (not shown) of the storage line CST may extend along a differentdirection to overlap at least a portion of a data line DL of acorresponding pixel. The storage line CST may be disposed in each of thetransmissive area TA and the reflective area RA.

The m-th data line DL_(m), the first gate electrode G1, a first sourceelectrode SE1, a first drain electrode DE1, a second source electrodeSE2, a second drain electrode DE2, a third source electrode SE3, a thirddrain electrode DE3 and a charge dividing electrode CDE are disposed onthe first insulating substrate 101 on which the n-th gate line GL_(n) isdisposed.

The m-th data line DL_(m) crosses the n-th gate line GL_(n) and extendsalong the second direction (substantially perpendicular to the firstdirection). An insulating layer 110 is interposed between the m-th dataline DL_(m) and the n-th gate line GL_(n), as shown in FIG. 2. The firstsource electrode SE1 and the second source electrode SE2 branch from them-th data line DL_(m) to partially overlap the n-th gate line GL_(n).The first drain electrode DE1 and the second drain electrode DE2 arespaced apart from the first source electrode SE1 and the second sourceelectrode SE2, respectively, to partially overlap the n-th gate lineGL_(n). The third source electrode SE3 branches from the second drainelectrode DE2 to partially overlap the n-th sub-gate line GL_(n)′. Thethird drain electrode DE3 is spaced apart from the third sourceelectrode SE3 to partially overlap the n-th sub-gate line GL_(n)′. Thecharge dividing electrode CDE overlaps at least a portion of the storageline CST of the transmissive area TA.

A transmissive pixel electrode TE and a reflective pixel electrode REare disposed on the first through third source electrodes SE1, SE2 andSE3, respectively, and the first through third drain electrodes DE1, DE2and DE3, respectively, and a protective layer 120 is interposedtherebetween. The transmissive pixel electrode TE, which includes atransparent conductive material, is disposed in the transmissive area TAand is connected to the first drain electrode DE1 through a contact holeformed through the protective layer 120. The reflective pixel electrodeRE, which includes a non-transparent conductive material, is disposed inthe reflective area RA and is connected to the second drain electrodeDE2 through a contact hole formed through the protective layer 120. Inan exemplary embodiment, the reflective pixel electrode RE may bedisposed only with the non-transparent conductive material layer.Additionally, the reflective pixel electrode RE may be formed by formingthe non-transparent conductive material layer on and/or under thetransparent conductive material layer that forms the transmissive pixelelectrode TE, and thereafter patterning the non-transparent conductivematerial layer to form a multilayer structure. The reflective pixelelectrode RE may be formed to have a concavo-convex portion on a surfacethereof (as shown in FIG. 2) such that the reflective pixel electrode REhas a high reflectance. The concavo-convex portion may be integrallyformed with the reflective pixel electrode RE or, alternatively, may beformed by patterning the protective layer 120 under the reflective pixelelectrode RE. When a width of one concavo-convex pattern of theconcavo-convex portion is defined as a pitch thereof, the pitch may beabout 4 micrometers (μm) to about 5 μm, and a distance between a mostrecessed portion and a most protruded portion (relative to a planedefined by an outer surface of the protective layer 120 or thereflective pixel electrode RE, as viewed along the vertical direction inFIG. 2) may be about 0.5 μm to about 2.5 μm.

As described above, a portion of the n-th gate line GL_(n), e.g., thefirst gate electrode GE1, the first source electrode SE1 and the firstdrain electrode DE1 form a first thin film transistor T1. Likewise, aportion of the n-th gate line GL_(n), e.g., a second gate electrode (notshown), the second source electrode SE2, and the second drain electrodeDE2 form a second thin film transistor T2, and a portion of the n-thsub-gate line GL_(n)′, e.g., a third gate electrode (not shown), thethird source electrode SE3, and the third drain electrode DE3 form athird thin film transistor T3. The third thin film transistor T3, thecharge dividing electrode CDE connected to the third drain electrode DE3of the third thin film transistor T3, and the storage line CST form avoltage controller.

Referring still to FIGS. 1 and 2, the second substrate 200 includes asecond insulating substrate 201. In addition, a transparent organiclayer 220, a light-blocking layer 211, a color filter layer 210 and acommon electrode CE are disposed on the second insulating substrate 201.

The transparent organic layer 220 has a predetermined thickness in onearea proximate to the second insulating substrate 201. Thelight-blocking layer 211 prevents light from leaking and thus includes anon-transparent material that absorbs light. The color filter layer 210covers the area in which the transparent organic layer 220 is disposedand a remaining area in which the transparent organic layer 220 is notdisposed. The transparent organic layer 220 and the color filter layer210 will be described in greater detail below.

The common electrode CE is disposed on the color filter layer 210 whilean insulating layer 213 is disposed therebetween and forms an electricfield with the transmissive pixel electrode TE and the reflective pixelelectrode RE to drive the liquid crystal layer 300.

A first polarizer 153 and a second polarizer 253 that has a polarizingaxis substantially perpendicular to a polarizing axis of the firstpolarizer 153 are disposed on outer surfaces of the first insulatingsubstrate 101 and the second insulating substrate 201, respectively. Aphase retardation film may be disposed between the first insulatingsubstrate 101 and the first polarizer 153 and/or between the secondinsulating substrate 201 and the second polarizer 253. For example, inthe exemplary embodiment shown in FIG. 2, a phase retardation film 151and a phase retardation film 251 are disposed on surfaces of the firstinsulating substrate 101 and the second insulating substrate 201,respectively, but alternative exemplary embodiments are not limitedthereto. For example, in other exemplary embodiments, the phaseretardation films 151 and/or 251 may be not be included on the firstinsulating substrate 101 and/or the second insulating substrate 201,respectively, such as when since a phase retardation value iscompensated by applying voltages having different voltage levels to thetransmissive area TA and the reflective area RA, for example.

An anti-glare part (not shown) may be disposed on at least one surfaceof each of the first polarizer 153, the second polarizer 253 and thephase retardation films 151 and 251 to prevent rainbow defects, such aswhen the concavo-convex portion of the reflective pixel electrode RE isdisposed on the reflective pixel electrode RE itself, since the rainbowdefects may occur due to reflected lights from the concavo-convexportion, which may interfere with each other.

In the anti-glare part, for example, non-conductive fine particles likesilica or conductive fine particles like gold are unevenly dispersed, tosubstantially reduce interference between the reflected lights. Thenon-conductive fine particles or the conductive fine particles may havea diameter equal to or less than about 40 μm. The anti-glare part mayhave a haze value, which is defined as a percentage ratio of scatteredlight and total transmitted light, of about 5 percent (%) to about 70%.

In an exemplary embodiment, a distance between the first substrate 100and the second substrate 200 in the transmissive area TA issubstantially equal to a distance between the first substrate 100 andthe second substrate 200 in the reflective area RA. Put another way, thetransmissive area TA and the reflective area RA may have a single cellgap. More specifically, when the concavo-convex portion is disposed onthe reflective pixel electrode RE (as shown in FIG. 2) after performinga patterning process to form the concavo-convex portion, a cell gapd_(R) of the reflective are RA, in which the reflective pixel electrodeRE is formed, may become slightly larger than a cell gap d_(T) of thetransmissive area TA, in which the transmissive pixel electrode TE isformed. However, since the difference between the cell gaps d_(R) andd_(T) is small (relative to a value of the cell gaps d_(R) and d_(T)themselves, for example), the transmissive area TA and the reflectivearea RA effectively have a single cell gap.

FIG. 3 is an equivalent circuit diagram showing a pixel of the liquidcrystal display of FIG. 1, and FIG. 4 is an equivalent circuit diagramshowing an n-th pixel when a gate signal is applied to the n-th gateline GL_(n) of the pixel FIG. 3.

Hereinafter, an exemplary embodiment of a method of driving a liquidcrystal display will be described in further detail with reference toFIGS. 1 through 4.

A first liquid crystal capacitor T-Clc, a second liquid crystalcapacitor R-Clc, a first storage capacitor T-Cst, and a second storagecapacitor R-Cst are disposed in the pixel having the first and secondthin film transistors T1 and T2, respectively.

More particularly, the first thin film transistor T1 includes the firstgate electrode GE1 connected to the n-th gate line GL_(n), the firstsource electrode SE1 connected to the m-th data line DL_(m), and thefirst drain electrode DE1 connected to the first liquid crystalcapacitor T-Clc. The first liquid crystal capacitor T-Clc is formed bythe transmissive pixel electrode TE connected to the first drainelectrode DE1, the common electrode CE facing the transmissive pixelelectrode TE and which receives a common voltage Vcom, and the liquidcrystal layer 300 disposed between the transmissive pixel electrode TEand the common electrode CE. The first storage capacitor T-Cst is formedby the transmissive pixel electrode TE, the storage line CST to whichthe common voltage Vcom is applied, and the insulating layer 110 and theprotective layer 120, which are interposed between the transmissivepixel electrode TE and the storage line CST.

The second thin film transistor T2 includes a second gate electrodeconnected to the n-th gate line GL_(n), the second source electrode SE2connected to the m-th data line DL_(m), and the second drain electrodeDE2 connected to the second liquid crystal capacitor R-Clc. The secondliquid crystal capacitor R-Clc is formed by the reflective pixelelectrode RE connected to the second drain electrode DE2, the commonelectrode CE facing the reflective pixel electrode RE and which receivesthe common voltage Vcom, and the liquid crystal layer 300 disposedbetween the reflective pixel electrode RE and the common electrode CE.The second storage capacitor R-Cst is formed by the reflective pixelelectrode RE, the storage line CST to which the common voltage Vcom isapplied, and the insulating layer 110 and the protective layer 120,which are interposed between the reflective pixel electrode RE and thestorage line CST.

A gate signal is applied to the n-th gate line GL_(n), and a data signalis applied to the m-th data line DL_(m). When the first and second thinfilm transistors T1 and T2, respectively, are turned on in response tothe gate signal applied through the n-th gate line GL_(n), the datasignal is applied to the transmissive pixel electrode TE and thereflective pixel electrode RE through the first and second thin filmtransistors T1 and T2.

Referring to FIGS. 3 and 4, when the gate signal is applied to the n-thgate line GL_(n), the first and second thin film transistors T1 and T2are turned on. Thus, the data signal applied to the m-th data lineDL_(m) is provided to the transmissive pixel electrode TE and thereflective pixel electrode RE of the first and second liquid crystalcapacitors T-Clc and R-Clc through the first and second thin filmtransistors T1 and T2, respectively. In this case, since the signalsapplied to the transmissive pixel electrode TE and the reflective pixelelectrode RE of the first and second liquid crystal capacitors T-Clc andR-Clc are identical, the first and second liquid crystal capacitorsT-Clc and R-Clc are charged with a first pixel voltage and a secondpixel voltage, respectively, which have a same voltage level.

The pixel further includes the n-th sub-gate line GL_(n)′ and the thirdthin film transistor T3, and the third thin film transistor T3 controlsa voltage level of the first and second pixel voltages charged in thetransmissive pixel electrode TE and the reflective pixel electrode RE,respectively.

The third thin film transistor T3 includes a third gate electrodeconnected to the n-th sub-gate line GL_(n)′, the third source electrodeSE3 connected to the reflective pixel electrode RE and the third drainelectrode DE3 connected to a down-capacitor Cdown and an up-capacitorCup.

As shown in FIG. 2, the down-capacitor Cdown is formed by the storageline CST, the charge dividing electrode CDE connected to the third drainelectrode DE3 and which partially overlaps the storage line CST, and theinsulating layer 110 interposed between the charge dividing electrodeCDE and the storage line CST. The up-capacitor Cup is formed by thetransmissive pixel electrode TE, the charge dividing electrode CDE thatpartially overlaps the transmissive pixel electrode TE, and theprotective layer 120 interposed between the charge dividing electrodeCDE and the transmissive pixel electrode TE.

The third thin film transistor T3 is turned on in response to a gatesignal applied to the n-th sub-gate line GL_(n)′ to output a voltagecontrol signal after the gate signal is applied to the n-th gate lineGL_(n). Thus, the reflective pixel electrode RE is electricallyconnected to the charge dividing electrode CDE by the third thin filmtransistor T3. Consequently, the voltage level of the first pixelvoltage charged in the first liquid crystal capacitor T-Clc and thevoltage level of the second pixel voltage charged in the second liquidcrystal capacitor R-Clc is controlled by the up-capacitor Cup and thedown-capacitor Cdown. Specifically, the voltage level of the first pixelvoltage increases and the voltage level of the second pixel voltagedecreases due to the up-capacitor Cup and the down-capacitor Cdown. Anamount of increase and decrease in the first and second pixel voltages,respectively, depends capacitances of the up-capacitor Cup and thedown-capacitor Cdown.

Thus, different voltages may be applied to the transmissive pixelelectrode TE and the reflective pixel electrode RE by forming thevoltage controller, as described above.

FIG. 5 is a graph of relative values of reflection transmission versusvoltage, in volts (V), illustrating an exemplary embodiment of a methodof controlling a light transmission amount and a light reflection amountaccording to applied voltages for a single cell gap in the liquidcrystal display of FIG. 1. In FIG. 5, a structure in which the phaseretardation films 151 and 251 are interposed between the firstinsulating substrate 101 and the first polarizer 153 and between thesecond insulating substrate 201 and the second polarizer 253,respectively, will be described, but it will be noted that additionalexemplary embodiments are not limited thereto. In an exemplaryembodiment, each of the phase retardation films 151 and 251 serves as acompensation film having a wavelength λ of about 550 nanometers (nm) anda retardation value Ro of λ/4 or, alternatively, λ/4+λ/2.

Referring to FIG. 5, in an exemplary embodiment, the reflective area RAand the transmissive area TA are driven in normally-black mode, and alight reflection amount of the reflective area RA and the lighttransmission amount of the transmissive area TA have different valuesaccording to voltages applied to the reflective pixel electrode RE andthe transmissive pixel electrode TE. As a result, a reflection curve Rdoes not match a transmission curve T. For example, a first appliedvoltage value (a) when the light reflection amount is at maximum is lessthan an applied voltage value (b) when the light transmission amount isat maximum. Therefore, when the same voltages are applied to thereflective pixel electrode RE and the transmissive pixel electrode TE,it is difficult to match the gray-scale in the reflective area RA withthe gray-scale in the transmissive area TA.

Thus, in an exemplary embodiment, the first pixel voltage and the secondpixel voltage that are applied to the transmissive pixel electrode TEand the reflective pixel electrode RE, respectively, are controlled bythe voltage controller, described in greater detail above, such that thereflection curve R is substantially identically matched to thetransmission curve T, as shown by the right-shifted reflection curve Rin FIG. 5. Specifically, when the voltage controller lowers the voltagelevel of the second pixel voltage, the voltage level of a voltageapplied to the liquid crystal layer 300 corresponding to the reflectivearea RA decreases, and the reflection curve R moves to the right, asshown in FIG. 5. Therefore, the reflection curve R may be substantiallyidentically matched to the transmission curve T, e.g., may besubstantially the same as the transmission curve T. As a result, thegray-scale of the reflective area RA is substantially identicallymatched with the gray-scale of the transmission area RA by applying thevoltages having the same voltage level. It will be noted that otherexemplary embodiments are not limited to the method of adjusting thetransmission curve T as shown in FIG. 5. Specifically, for example, thetransmission curve T may be adjusted by decreasing the voltage level ofthe second pixel voltage or, alternatively, by increasing the voltagelevel of the first pixel voltage (not shown).

When the phase retardation film is not included, the gray-scale of thetransmissive area TA may be matched with the gray-scale of thereflective area RA by controlling the first and second pixel voltages.Specifically, for example, when the phase retardation film is notincluded, the reflective area RA may be driven in normally-white modeand the transmissive area TA may be driven in normally-black mode.However, the gray-scale of the transmissive area TA is matched to thegray-scale of the reflective area RA by controlling the first and secondpixel voltages applied to the transmissive area TA and the reflectivearea RA, respectively.

The first pixel voltage and the second pixel voltage may have differentvalues, based on the cell gap difference (described above) between thereflective area RA and the transmissive area TA. For example, when thefirst pixel voltage is about 1 volt (V) and the cell gap d_(R) (FIG. 2)of the reflective area RA is less than the cell gap d_(T) of thetransmissive area TA, the second pixel voltage may be about 0.4 V toabout 1 V. When the cell gap d_(R) of the reflective area RA is the sameas the cell gap d_(T) of the transmissive area TA, the second pixelvoltage may be about 0.3 V to about 0.8 V. In addition, when the cellgap d_(R) of the reflective area RA is larger than the cell gap d_(T) ofthe transmissive area TA, the second pixel voltage may be about 0.2 V toabout 0.7 V.

That is, an alignment direction of liquid crystal molecules in theliquid crystal layer 300 is controlled according to voltages applied tothe transmissive area TA and the reflective area RA. As a result, phaseretardation values of light passing through the liquid crystal layer 300corresponding to the transmissive area TA and the reflective area RA areeffectively controlled to have a same value, thereby matching thegray-scale in the transmissive area TA with the gray-scale in thereflective area RA in an LCD having a signal cell gap. In addition,since the light provided to the reflective area RA successively travelsthrough the second insulating substrate 201, the color filter layer 210,the insulating layer 213, the common electrode CE, the liquid crystallayer 300, the reflective pixel electrode RE, the liquid crystal layer300, the common electrode CE, the insulating layer 213, the color filterlayer 210, and the second insulating substrate 201, the light passesthrough the liquid crystal layer 300 and the color filter layer 210 twotimes. In contrast, the light provided to the transmissive area TAsuccessively travels through the first insulating substrate 101, theinsulating layer 110, the protective layer 120, the transmissive pixelelectrode TE, the liquid crystal layer 300, the common electrode CE, theinsulating layer 213, the color filter layer 210, and the secondinsulating substrate 201, and thus the light passes through the liquidcrystal layer 300 and the color filter layer 210 only one time.Therefore, when the light travels through the liquid crystal layer 300and the color filter layer 210 two times, of which a light absorbance isrelatively higher than other materials, parts of the light provided tothe reflective area RA is absorbed by the liquid crystal layer 300 andthe color filter layer 210, so that the amount of the light exitingthrough the reflective area RA may decrease. Accordingly, a light amountdifference may occur between the lights traveling through the reflectivearea RA and the transmissive area TA, and the gray-scales of thereflective and transmissive areas RA and TA are not matched with eachother.

Thus, in an exemplary embodiment, the transparent organic layer 220 isdisposed in an area of the color filter layer 210 corresponding to thereflective area RA, such that the light amount of the light travelingthrough the reflective area RA may increase and the difference in thelight amount between the reflective and transmissive areas RA and TA maybe minimized.

The transparent organic layer 220 has the predetermined thicknessproximate to the area of the second insulating substrate 201. Thetransparent organic layer 220 includes an organic material having alight absorbance less than that a light absorbance of the color filterlayer 210. The transparent organic layer 220 is disposed on the secondinsulating substrate 201 to correspond to the reflective area RA of thefirst substrate 100.

The color filter layer 210 covers the area where the transparent organiclayer 220 is disposed and a remaining area where the transparent organiclayer 220 is not disposed. The color filter layer 210 is disposed on thesecond insulating substrate 201 and includes materials that produce red,blue, green and white colors, for example, to display colors during thelight passing therethrough. In an exemplary embodiment, since thetransparent organic layer 220 is formed to have the predeterminedthickness in the area where the color filter layer 210 is disposed, athickness of the color filter layer 210 in the area where thetransparent organic layer 220 is disposed becomes thinner than athickness of the color filter layer 210 in the remaining area where thetransparent organic layer 220 is not disposed after forming the colorfilter layer 210. The area where the color filter layer 210 has arelatively thin thickness has a light absorbance less than the areawhere the color filter layer 210 has a relatively thick thickness. Thus,the light traveling through the area has a higher light amount than thatof the light traveling through the remaining area, to thereby compensatefor the difference between the amount of light passing through thetransmissive area TA, which has a relatively high light amount, and theamount of light passing through the reflective area RA, which has arelatively low light amount. Accordingly, the amounts of light in thereflective area RA and the transmissive area TA are uniform.

In an exemplary embodiment, the transparent organic layer 220 isdisposed on the color filter layer 210 to improve the light amount ofthe reflective area RA, however, alternative exemplary embodiments arenot limited thereto. For example, instead of forming the transparentorganic layer 220 as described above, a penetrating hole 220′, throughwhich light easily passes, may be formed in the color filter layer 210,as shown in FIG. 6, which will now be described in further detail.

FIG. 6 is a partial cross-sectional view of an exemplary embodiment of aliquid crystal display according to the present invention. Moreparticularly, FIG. 6 shows a color filter layer 210 through which thepenetrating hole 220′ is formed. In FIG. 6, the same referencecharacters denote the same or like components as described in greaterdetail above with reference to FIGS. 1 through 5; accordingly, anyrepetitive detailed description thereof will hereinafter be simplifiedor omitted.

In an exemplary embodiment, the penetrating hole 220′, which exposes atleast a portion of a second insulating substrate 201, is formed in acolor filter layer 210 corresponding to a reflective area RA, to improvea light amount of a light passing through the reflective area RA. In oneor more exemplary embodiments, a plurality of the penetrating holes 220′may be formed. Since the color filter layer 210 is not disposed in thearea through which the penetrating hole 220′ is formed, the lightdirectly passes through the penetrating hole 220′ without passingthrough the color filter layer 210. Therefore, no light is absorbed bythe color filter layer 210 and the light amount of the light increases.The penetrating hole 220′ is not disposed in a remaining area of thecolor filter layer 210 except for the area where the penetrating hole220′ is formed of the color filter layer 210, and the light passesthrough the remaining area of the color filter layer 210, to therebydisplay colors. As a result, the light amount of the light may beimproved without decreasing color reproducibility.

An insulating layer 213 is disposed on the color filter layer 210, inwhich the penetrating hole 220′ is formed, and the color filter layer210 is not disposed in the area in which the penetrating hole 220′ isformed. Thus, an upper surface of the insulating layer 213 has asubstantially concave shape in the area in which the penetrating hole220′ is formed. When the penetrating hole 220′ is formed in the colorfilter layer 210, the cell gap d_(R) of the reflective area RA becomesgreater than or equal to the cell gap d_(T) of the transmissive area TAsince a cell gap of the area in which the penetrating hole 220′ isformed becomes larger than a cell gap of the remaining area.

In an exemplary embodiment, a planarization layer 122 is disposed on thereflective pixel electrode RE. The transmissive pixel electrode TE isdisposed on the planarization layer 122.

The planarization layer 122 is disposed in order to decrease a spotdefect caused by the concavo-convex portion of the transmissive pixelelectrode TE. The planarization layer planarizes a surface of the firstsubstrate 100 and, as a result, liquid crystal molecules included in theliquid crystal layer 300 are effectively prevented from becomingmisaligned due a height difference in the concavo-convex portion.

FIGS. 7A through 7E are plan views of additional exemplary embodimentsof a liquid crystal display according to the present invention. In FIGS.7A through 7E, the same reference characters denote the same or likecomponents as described in greater detail above with reference to theprevious drawings; accordingly, any repetitive detailed descriptionthereof will hereinafter be simplified or omitted. Referring now toFIGS. 7A through 7E, a transmissive pixel electrode TE, a reflectivepixel electrode RE and a common electrode CE will be described infurther detail.

In FIGS. 7A through 7E, the transmissive pixel electrode TE and thereflective pixel electrode RE have a predetermined area, but exemplaryembodiments are not limited thereto. For example, the transmissive pixelelectrode TE and the reflective pixel electrode RE may be also providedwith various area ratios. An area ratio of the transmissive pixelelectrode TE and the reflective pixel electrode RE may be 7:3 ineffective aperture area of each pixel except an area of thelight-blocking layer 211. Preferably, assuming the effective aperturearea of each pixel except the light-blocking layer 211 being 100% of apixel area, the reflective pixel electrode RE may have an area of about30% of the pixel area or more. This is because a luminance of thetransflective LCD rarely increases even though direct light from the sunincreases if the reflective pixel has an area under 30% of the pixelarea.

In an LCD according to one or more exemplary embodiments, at least onedividing pattern is formed on a transmissive pixel electrode TE, areflective pixel electrode RE, and a common electrode CE to divide aliquid crystal layer 300 into a plurality of domains, to therebysubstantially improve a viewing angle of the LCD. The domains may havethe same area or, alternatively, different areas.

The dividing pattern is formed on at least one of the transmissive pixelelectrode TE, the reflective pixel electrode RE and the common electrodeCE, and the dividing pattern may have a slit shape (hereinafter,referred to as a slit portion) when viewed from above a plan view of theLCD, an embossed shape (hereinafter, referred to as an embossed portion)and/or a hole shape (hereinafter, referred to as a hole portion) tocontrol a director of a liquid crystal, but exemplary embodiments arenot limited thereto. In another exemplary embodiment, the embossedportion E1 forms a pyramidal pattern or a hemispheric pattern.

Referring now to FIG. 7A, in an exemplary embodiment, slit portions S1and S2 are formed in the transmissive pixel electrode TE and the commonelectrode CE of the second substrate 200 corresponding to thetransmissive pixel electrode TE as the dividing pattern. An embossedportion E1 is formed in the reflective pixel electrode RE. In anexemplary embodiment, the embossed portion E1 forms a close-packedhexagonal pattern, as shown in FIG. 7A.

In alternative exemplary embodiments, the embossed portions E1 and theslit portions S1 and S2 may be arranged differently than as shown inFIG. 7A, e.g., the embossed portions E1 and the slit portions S1 and S2may be replaced with each other (e.g., swapped) and/or disposed in asame area. In addition, the slit portions S1 and S2 or the embossedportion E1 may be formed by patterning at least one of the transmissivepixel electrode TE, the reflective pixel electrode RE, and the commonelectrode CE.

As shown in FIG. 7B, in another exemplary embodiment, the slit portionsS1 and S2 or the embossed portions E1 are formed in the transmissivepixel electrode TE, the common electrode CE corresponding to thetransmissive pixel electrode TE and the reflective pixel electrode RE.

As shown in FIG. 7C, in yet another exemplary embodiment, the slitportions S1 and S2 or the embossed portions E1 are formed in thetransmissive pixel electrode TE, the reflective pixel electrode RE, andthe common electrode CE that corresponds to the transmissive pixelelectrode TE and the reflective pixel electrode RE.

As shown in FIG. 7D, in another exemplary embodiment, the slit portionsS1 and S2 or the embossed portions E1 are formed in the transmissivepixel electrode TE and the common electrode CE corresponding to thetransmissive pixel electrode TE and the reflective electrode RE.

As shown in FIG. 7E, in another exemplary embodiment, the slit portionsS1 and S2, or the embossed portion E1, is formed through thetransmissive pixel electrode TE, a hole portion H is formed in thecommon electrode CE corresponding to the transmissive pixel electrodeTE, and the slit portions S1 and S2 or the embossed portions E1 areformed through the common electrode CE corresponding to the reflectivepixel electrode RE.

Referring now to FIGS. 7A through 7E, the dividing pattern formed in thetransmissive pixel electrode TE and the reflective pixel electrode REmay be in the form of the slit portions S1 and S2. Moreover, thedividing pattern formed in the common electrode CE may be prepared inthe form of the slit portions S1 and S2, as shown in FIGS. 7A through7D, or in the form of the hole portion H, as shown in FIG. 7E. In stillanother exemplary embodiment, the dividing pattern, which is formedthrough the transmissive pixel electrode TE and the reflective pixelelectrode RE, may be the form of the embossed portions E1 instead of theslit portions S1 and S2 or the hole portions H.

When the dividing pattern is in the form of the slit portions S1 and S2in the transmissive pixel electrode TE, the reflective pixel electrodeRE, and the common electrode CE, the slit portions S2 formed in thecommon electrode CE are arranged substantially parallel to the slitportions S1 of the transmissive pixel electrode or the reflective pixelelectrode RE and positioned at an area corresponding to between the slitportions S1 of the transmissive pixel electrode TE or the reflectivepixel electrode RE. The slit portions S1 of the transmissive pixelelectrode TE and the common electrode CE are inclined with respect tothe n-th gate line GL_(n) or the m-th data line DL_(m) and aresymmetrical with respect to each other with reference to an imaginaryline parallel to the n-th gate line GL_(n), and the slit portions S2 ofthe transmissive pixel electrode TE and the common electrode CE isformed to be inclined to the n-th gate line GL_(n) or the m-th data lineDL_(m) and is formed to be symmetrical with respect to each other withreference to an imaginary line parallel to the n-th gate line GL_(n). Asshown in FIG. 7E, when the slit portion S1 is disposed in thetransmissive pixel electrode TE and the hole portion H is disposed inthe common electrode CE, the slit portion S1 of the transmissive pixelelectrode TE may be disposed in substantially parallel to the n-th gateline GL_(n) and the m-th data line DL_(m) to form a plurality ofdomains, and the hole portion H may be formed at a positioncorresponding to a center portion of each domain. In another exemplaryembodiment, the hole portion H formed at the center portion of eachdomain may be replaced with the embossing portions E1.

A concavo-convex portion is disposed on the reflective pixel electrodeRE, and a pretilt angle of the liquid crystal molecules of the liquidcrystal layer is controlled by the concavo-convex portion, so that thereflective pixel electrode RE of an LCD according to an exemplaryembodiment may not need the slit portions S1 and S2.

Liquid crystal molecules (not shown) of the liquid crystal layer 300(FIG. 2) adjacent to the slit portions S1 and S2 may be tilted at apredetermined angle by the slit portions S1 and S2 of the transmissivepixel electrode TE and the common electrode CE, thereby substantiallyimproving the viewing angle of the LCD according to an exemplaryembodiment.

FIG. 8A is a plan view of one exemplary embodiment of an LCD accordingto the present invention, FIG. 8B is a partial cross-sectional viewtaken along line B-B′ of FIG. 8A, and FIG. 8C is a partialcross-sectional view taken along line C-C′ of FIG. 8A.

Referring to FIGS. 8A to 8C, the concavo-convex portion includes a basesurface BS and a plurality of protrusions PR protruding from the basesurface BS. The base surface BS is substantially parallel to a surfaceof the first insulating substrate. The protrusions PR may be arranged onthe base surface BS regularly.

Each protrusion PR may be provided with a honeycomb structure in a planview, but alternative exemplary embodiments are not limited thereto.Each protrusion PR has various shapes such as a shape of a circle, anellipse or a polygon in a plan view.

The protrusions PR may have a same or different width when viewed indifferent directions in a plan view. When the protrusions PR arearranged with a regular width in one direction, the width in onedirection is referred to as a pitch. The pitch may be of about 10 μm ormore. In case that each of the protrusions PR has a pitch less than 10μm, for example, about 4 μm to about 6 μm, a reflection luminance of thereflective pixel electrode RE is not enough to be bright. The reflectionluminance generally increases as the pitch increases.

Referring to FIGS. 8B and 8C, the protrusions PR have different pitcheswhen viewed in different directions in a plan view. The protrusions PRhave a first pitch P1 in a first direction D1 and a second pitch P2 in asecond direction D2 substantially perpendicular to the first directionD1. The first pitch P1 may be different from the second pitch P2. Whenthe first insulating substrate is provided with a rectangular shape andthe first direction D1 is substantially parallel to longer sides of therectangular shape, the first pitch P1 may have 1.1 times or more thesecond pitch P2. The difference between the first pitch P1 and thesecond pitch P2 is to compensate for the visibility difference betweenthe first direction D1 and the second direction D2 of the transflectiveLCD.

Each protrusion PR has a contact angle θ at which a surface of eachprotrusion PR meets the base surface BS. Each protrusion PR has thecontact angle θ of about 10° to about 40°. If the contact angle θ isless than 10°, the reflection luminance difference with respect to anangle between the liquid crystal panel and an external light source suchas the sun becomes larger. If the contact angle θ is more than 40°, theprotrusions PR are hard to be made.

FIG. 9A is a graph showing a reflection luminance of a reflective pixelelectrode RE according to a solar altitude when the protrusions PR areprovided with a pitch of 10 μm, 15 μm, or 20 μm in one direction. Thereflection luminance is measured using the Specular method. According toFIG. 9A, the reflection luminance increases as the pitch increases whenthe solar altitude is in a range of about 30° to about 40°.

FIG. 9B is a graph showing a reflection luminance of a reflective pixelelectrode RE according to a solar altitude and the contact angle θ ofthe protrusions PR when the intensity of illumination is set to about80,000 lux. In FIG. 9B, a graph P, a graph Q, a graph R and a graph Scorrespond to the contact angles θ of 10°, 11°, 12°, and 14.5°,respectively.

Referring to FIG. 9B, a decrease of the reflection luminance accordingto an increase of the solar altitude generally becomes larger as thecontact angle θ becomes smaller. Thus, it is preferable for theprotrusions PR to have the contact angle θ of 10° or more, morepreferably to have the contact angle θ of 14° or more, to show arelatively uniform reflection luminance regardless of the solaraltitude.

FIG. 10 is a partial cross-sectional view taken along line B-B′ of FIG.8A according to another exemplary embodiment of the present invention.

Referring to FIG. 10, the highest point of each protrusion PR does notcoincide with its center in a plan view. In this case, when eachprotrusion PR is taken along a plane that includes the center thereonand is substantially perpendicular to a surface of the first insulatingsubstrate, a cross-section of each protrusion PR is providedasymmetrically with respect to the center.

When each protrusion PR is taken along a plane that includes the centerthereon and is substantially perpendicular to the surface of the firstinsulating substrate to allow each protrusion PR to have a largestpitch, the cross-section has a distance d1 from a point on the basesurface BS corresponding to the highest point of each protrusion PR toone end of the each protrusion PR and a distance d2 from the point onthe base surface BS corresponding to the highest point to the other endof the each protrusion PR. The distance d1 is different from thedistance d2.

Because each of the protrusions PR is provided asymmetrically withrespect to the center, the protrusions PR reflect the external lightwith different intensity in different directions according to a locationof an external light source such as the solar altitude. Therefore, thereflection luminance can be maximized by adjusting surfaces of theasymmetric protrusions with respect to the location of the externallight source.

FIG. 11 is a graph showing a reflection luminance of a reflective pixelelectrode RE according to a solar altitude when the protrusions PR areprovided with a pitch of 10 μm, 15 μm, or 25 μm in one direction, d2/d1is 1.2, and a relatively slightly inclined plane faces a direction towhich the external light travels. Referring FIG. 11, the reflectionluminance when each protrusion is asymmetrical is higher than that wheneach protrusion is symmetrical such as FIG. 9A.

As described above, the reflective pixel electrode RE having theprotrusions PR gives a high visibility by adjusting the contact angle θand the shape of the protrusions PR according to the altitude of theexternal light source.

FIG. 12 is a plan view of yet another exemplary embodiment of an LCDaccording to the present invention, and FIG. 13 is an equivalent circuitdiagram of a pixel of the LCD of FIG. 12. In FIGS. 12 and 13, a voltagecontroller is configured to have a circuit configuration different fromin the additional exemplary embodiments of the voltage controller ofdescribed in greater detail above. In addition, the same referencecharacters have been used to refer to the same or like componentsthroughout the drawings, and thus any repetitive detailed descriptionwill hereinafter be simplified or omitted.

Referring to FIGS. 2, 12 and 13, a voltage controller according to anexemplary embodiment includes a third thin film transistor T3 having asource electrode SE3 connected to a transmissive pixel electrode TE.

As shown in FIG. 12, n+p gate lines GL₁, . . . , GL_(n), GL_(n+1), . . ., GL_((n+p)−1), GL_(n+p) and m+q data lines DL₁, . . . , DL_(m),DL_(m+1), . . . , DL_((m+q)−1), DL_(m+q) are disposed on a firstinsulating substrate 101 (FIG. 2), and each pixel includes one gate lineGL of the n+p gate lines GL₁, . . . , GL_(n), GL_(n+1), . . . ,GL_((n+p)−1), GL_(n+p) and one data line DL of the m+q data lines DL₁, .. . , DL_(m), DL_(m+1), . . . , DL_((m+q)−1), DL_(m+q). In FIG. 12, forpurposes of description, a pixel including an n-th gate line GL_(n), an(n+1)th gate line GL_(n+1), and m-th data line DL_(m) is shown and willbe described in further detail, but exemplary embodiments are notlimited thereto. In an exemplary embodiment, each pixel hassubstantially the same structure and function.

In the first substrate 100, the pixel including the n-th gate lineGL_(n), a gate electrode of the n-th gate line GL_(n) (not specificallylabeled in FIG. 12), and a storage line CST is disposed on the firstinsulating substrate 101 (FIG. 2).

The n-th gate line GL_(n) extends along a first direction on the firstinsulating substrate 101. The (n+1)th gate line GL_(n+1) is spaced apartfrom the n-th gate line GL_(n) disposed substantially parallel to then-th gate line GL_(n) to apply a gate signal to a next pixel, e.g., an(n+1)th pixel. The gate electrode may branch from the n-th gate lineGL_(n) or (n+1)th gate line GL_(n+1), or may be disposed on at least aportion of the n-th gate line GL_(n) or (n+1)th gate line GL_(n+1). Thestorage line CST is disposed between the n-th gate line GL_(n) and the(n+1)th gate line GL_(n+1) substantially parallel to the n-th gate lineGL_(n) and the (n+1)th gate line GL_(n+1). The storage line CST isspaced apart from the n-th gate line GL_(n) and the (n+1)th gate lineGL_(n+1). The storage line CST may extend along a different directionfrom the first direction, e.g., in a second direction substantiallyperpendicular to the first direction. The storage line CST is disposedin a portion of an area of the transmissive area TA and the reflectivearea RA.

The m-th data line DL_(m), a first source electrode SE1, a first drainelectrode DE1, a second source electrode SE2, a second drain electrodeDE2, a third source electrode SE3, a third drain electrode DE3, and acharge dividing electrode CDE are arranged on the first insulatingsubstrate 101 on which the n-th gate line GL_(n) is formed. Since thefirst and second source electrodes SE1 and SE2 are connected to the m-thdata line DL_(m).

The m-th data line DL_(m) crosses the n-th gate line GL_(n) and the(n+1)th gate line GL_(n+1) and includes an insulating layer 110 disposedtherebetween, and extends along the second direction. The first sourceelectrode SE1 and the second source electrode SE2 branch from the m-thdata line DL_(m) to partially overlap the n-th gate line GL_(n). Thefirst drain electrode DE1 and the second drain electrode DE2 are spacedapart from the first source electrode SE1 and the second sourceelectrode SE2, respectively, to partially overlap the n-th gate lineGL_(n). The third source electrode SE3 partially overlaps the (n+1)thgate line GL_(n+1) and is connected to a reflective pixel electrode REthat will be described later. The third drain electrode DE3 is spacedapart from the third source electrode SE3 to partially overlap the(n+1)th gate line GL_(n+1). The charge dividing electrode CDE overlapsthe storage line CST of the transmissive area TA.

A transmissive pixel electrode TE and a reflective pixel electrode REare disposed on the first through third source electrodes SE1, SE2 andSE3, respectively, and the first through third drain electrodes DE1, DE2and DE3, respectively, while the protective layer 120 is disposedtherebetween. The transmissive pixel electrode TE is disposed in thetransmissive area TA and connected to the first drain electrode DE1through a contact hole formed in the protective layer 120. Thereflective pixel electrode RE is disposed in the reflective area RA andis connected to the second drain electrode DE2 and the third sourceelectrode SE3 through a contact hole formed in the protective layer 120.A first thin film transistor T1 is formed by a portion of the n-th gateline GL_(n), the first source electrode SE1 and the first drainelectrode DE1, a second thin film transistor T2 is formed by a portionof the n-th gate line GLn, the second source electrode SE2 and thesecond drain electrode DE2, while a third thin film transistor T3 isformed by a portion of the (n+1)th gate line GL_(n+1), the third sourceelectrode SE3 and the third drain electrode DE3. The third thin filmtransistor T3, the charge dividing electrode CDE connected to the drainelectrode DE3 of the third thin film transistor T3, and the storage lineCST form the voltage controller.

Referring now to FIG. 13, when a gate signal is applied to the n-th gateline GL_(n), the first thin film transistor T1 and the second thin filmtransistor T2 are turned on. Thus, a data signal applied to the m-thdata line DL_(m) is provided to the transmissive pixel electrode TE of afirst liquid crystal capacitor T-Clc and the reflective pixel electrodeRE of a second liquid crystal capacitor R-Clc through the first thinfilm transistor T1 and the second thin film transistor T2. Since thesignal applied to the transmissive pixel electrode TE of the firstliquid crystal capacitor T-Clc is the same as the signal applied to thereflective pixel electrode RE of the second liquid crystal capacitorR-Clc, the first and second liquid crystal capacitors T-Clc and R-Clcare charged with a first pixel voltage and a second pixel voltage havingthe same voltage level.

The third thin film transistor T3 controls voltage levels of the firstand second pixel voltages charged in the transmissive pixel electrode TEand the reflective pixel electrode RE, respectively. The third thin filmtransistor T3 includes a third gate electrode connected to the n-th gateline GL_(n+1), the third source electrode SE3 connected to thereflective pixel electrode RE, and the third drain electrode DE3connected to a down-capacitor Cdown and an up-capacitor Cup.

The down-capacitor Cdown is formed by the storage line CST, the chargedividing electrode CDE partially overlapped with the storage line CSTand connected to the third drain electrode DE3, and the insulating layer110 interposed between the charge dividing electrode CDE and the storageline CST. The up-capacitor Cup is formed by the transmissive pixelelectrode TE, the charge dividing electrode CDE partially overlappedwith the transmissive pixel electrode TE, and the protective layer 120interposed between the charge dividing electrode CDE and thetransmissive pixel electrode TE.

The third thin film transistor T3 is turned on in response to a gatesignal applied to the (n+1)th gate line GL_(n+1) to output a voltagecontrol signal after the gate signal is applied to the n-th gate lineGL_(n). Then, the reflective pixel electrode RE is electricallyconnected to the charge dividing electrode CDE by the third thin filmtransistor T3. Therefore, the voltage levels of the first pixel voltagecharged in the first liquid crystal capacitor T-Clc and the second pixelvoltage charged in the second liquid crystal capacitor R-Clc arecontrolled by the up-capacitor Cup and the down-capacitor Cdown. Moreparticularly, the voltage level of the first pixel voltage increases andthe voltage level of the second pixel voltage decreases by theup-capacitor Cup and the down-capacitor Cdown. An increase and decreasein the first and second pixel voltages, respectively, depends oncapacitances of the up-capacitor Cup and the down-capacitor Cdown.

FIG. 14 is a plan view of yet another exemplary embodiment of an LCDaccording to the present invention. In an exemplary embodiment shown inFIG. 14, different data signals are applied to each of the transmissivepixel electrode TE and the reflective pixel electrode PE such thatdifferent voltages are applied thereto. In addition, in an exemplaryembodiment, a liquid crystal layer 300 (FIG. 2) interposed between afirst substrate 100 and a second substrate 200 is divided into aplurality of areas.

Hereinafter, only different elements from those of the additionalexemplary embodiments described in greater detail above will bedescribed with reference to FIGS. 1 and 14. In addition, the samereference characters in FIG. 14 denote the same or like elements in thepreviously-described exemplary embodiments, and thus any repetitivedetailed description thereof will be omitted.

The first substrate 100 includes a first insulating substrate 101 onwhich pixels, each having a reflective area RA and a transmissive areaTA, are disposed. In an exemplary embodiment, n+p gate lines GL_(n), . .. , GL_(n), GL_(n+1), . . . , GL_((n+p)−1), GL_(n+p), m+q data linesDL₁, . . . , DL_(m), DL_(m+1), . . . , DL_((m+q)−1), DL_(m+q), and m+q′sub-data lines DL₁′, . . . , DL_(m)′, DL_(m+1)′, . . . , DL_((m+q)−1)′,DL_(m+q)′, which are disposed substantially parallel to and spaced apartfrom the m+q data lines DL₁, . . . , DL_(m), DL_(m+1), . . . ,DL_((m+q)−1), DL_(m+q), are disposed on the first insulating substrate101. Each pixel includes one gate line GL of the n+p gate lines GL_(n),. . . , GL_(n), GL_(n+1), . . . , GL_((n+p)−1), GL_(n+p), one data lineDL of the m+q data lines DL₁, . . . , DL_(m), DL_(m+1), . . . ,DL_((m+q)−1), DL_(m+q), and one sub-data line DL′ of the sub-data linesDL₁′, . . . , DL_(m)′, DL_(m+1)′, . . . , DL_((m+q)−1)′, DL_(m+q)′. InFIGS. 14 and 15, for purposes of description, a pixel including the n-thgate line GLn, the m-th data line DLm, and the m-th sub-data lineDL_(m)′ is shown and will be described in greater detail herein, butalternative exemplary embodiments are not limited thereto. In anexemplary embodiment, each pixel has substantially the same structureand function.

The n-th gate line GL_(n) extends in a first direction on the firstinsulating substrate 101. The m-th data line DL_(m), the m-th sub-dataline DL_(m)′, a first source electrode SE1, a first drain electrode DE1,a second source electrode SE2, a second drain electrode DE2, and astorage line CST are disposed on the first insulating substrate 101 onwhich the n-th gate line GL_(n) is disposed.

The m-th data line DL_(m) and the m-th sub-data line DL_(m)′ extend in asecond direction, substantially perpendicular to the first direction, tocross the n-th gate line GL_(n) and having an insulating layer 110disposed therebetween.

The first source electrode SE1 and the second source electrode SE2branch from the m-th data line DL_(m) and the m-th sub-data lineDL_(m)′, respectively, to partially overlap the n-th gate line GL_(n).The first drain electrode DE1 and the second drain electrode DE2 arespaced apart from the first source electrode SE1 and the second sourceelectrode SE2, respectively, to partially overlap the n-th gate lineGL_(n).

A transmissive pixel electrode TE and a reflective pixel electrode REare disposed on the first source electrode SE1 and the second sourceelectrode SE2 and the first drain electrode DE1 and the second drainelectrode DE2, while a protective layer 120 is disposed therebetween.The transmissive pixel electrode TE is disposed in the transmissive areaTA, has a transparent conductive material, and is connected to the firstdrain electrode DE1 through a contact hole formed through the protectivelayer 120. The reflective pixel electrode RE is disposed in thereflective area RA, has a non-transparent conductive material, and isconnected to the second drain electrode DE2 through a contact holeformed through the protective layer 120.

The reflective pixel electrode RE may have a concavo-convex portiondisposed on a surface thereof to increase a reflectance of the same. Theconcavo-convex portion may be integrally formed with the reflectivepixel electrode RE and/or may be formed by patterning the protectivelayer 120 disposed under the reflective pixel electrode RE.

A second substrate 200 includes a second insulating substrate 201, and atransparent organic layer 220, a light-blocking layer 211, a colorfilter layer 210 and a common electrode CE are disposed on the secondinsulating substrate 201.

At least one dividing pattern is formed in one of the transmissive pixelelectrode TE, the reflective pixel electrode RE and the common electrodeCE to divide a liquid crystal layer 300 into domains. Each domain mayhave a same area or a different area. The dividing pattern is formed tohave a slit shape (hereinafter, referred to as slit portions S1 and S2)to control an alignment direction of the liquid crystal layer 300. In anexemplary embodiment, the slit portions S1 and S2 are formed in thetransmissive pixel electrode TE and the common electrode CE; however itwill be noted that alternative exemplary embodiments are not limitedthereto or thereby. For example, the slit portions S1 and S2 may bedisposed in the reflective pixel electrode RE. In addition, the dividingpattern may have an embossed shape and/or a hole shape.

Thus, in an exemplary embodiment, a portion of the n-th gate lineGL_(n), the first source electrode SE1, and the first drain electrodeDE1 form a first thin film transistor T1, and a portion of the n-th gateline GL_(n), a second source electrode SE2, and a second drain electrodeDE2 form a second thin film transistor T2.

Referring to FIG. 14, when a gate signal is applied to the n-th gateline GL_(n), the first thin film transistor T1 and the second thin filmtransistor T2 are turned on in response to the gate signal to output afirst data signal and a second data signal, respectively. Thus, thefirst data signal applied to the m-th data line DL_(m) is applied to thetransmissive pixel electrode TE through the first thin film transistorT1 to charge the transmissive pixel electrode TE, and the second datasignal applied to the m-th sub-data line DL_(m)′ is applied to thereflective pixel electrode RE through the second thin film transistor T2to charge the reflective pixel electrode RE. In this case, since them-th data line DL_(m) and the m-th sub-data line DL_(m)′ may applydifferent data signals from each other, a first pixel voltage and asecond pixel voltage having different voltage levels may be applied tothe transmissive pixel electrode TE and the reflective pixel electrodeRE, respectively.

As described above, since different voltages are applied to thetransmissive pixel electrode TE and the reflective pixel electrode RE,alignment angles of liquid crystal molecules included in the liquidcrystal layer 300 corresponding to the transmissive area TA and thereflective area RA are controlled differently from one another. As aresult, a phase retardation value of light passing through the liquidcrystal layer 300 of the transmissive pixel electrode TE may besubstantially the same as a phase retardation value of light passingthrough the liquid crystal layer 300 of the reflective pixel electrodeRE. Accordingly, a gray-scale of the transmissive area TA is matchedwith a gray-scale of the reflective area RA in an LCD having a signalcell gap. In addition, the dividing pattern is disposed in thetransmissive pixel electrode TE and the reflective pixel electrode RE toform the domains, thereby substantially improving a side visibility andgreatly widening a viewing angle of the LCD.

FIG. 15 is a plan view of still another exemplary embodiment of an LCDaccording to the present invention. In an exemplary embodiment,different data signals are applied to a transmissive pixel electrode TEand a reflective pixel electrode RE to provide different voltages to thetransmissive pixel electrode TE and the reflective pixel electrode RE,thereby providing a transflective LCD with a single cell gap. Inaddition, in an exemplary embodiment, the transmissive pixel electrodeTE may be divided into two areas, to which different pixel voltages areapplied, and a liquid crystal layer 300 interposed between a firstsubstrate 100 and a second substrate 200 is divided into a plurality ofdomains.

Hereinafter, only different elements from those of previously-describedadditional exemplary embodiments will be described in further detailwith reference to FIGS. 1 and 15. In addition, the same referencecharacters in FIG. 14 denote the same or like elements in the previousdrawings, and thus any repetitive detailed description thereof will beomitted.

A first substrate 100 includes a first insulating substrate 101 onpixels, each having a reflective area RA and a transmissive area TA, areformed. n+p gate lines GL₁ . . . , GL_(n), GL_(n+1), . . . ,GL_((n+p)−1), GL_(n+p), m+q data lines DL₁, . . . , DL_(m), DL_(m+1), .. . , DL_((m+q)−1), DL_(m+q), and m+q′ sub-data lines DL₁′, . . . ,DL_(m)′, DL_(m+1)′, . . . , DL_((m+q)−1)′, DL_(m+q)′ that aresubstantially parallel to and spaced apart from the M data lines DL₁, .. . , DL_(m), DL_(m+1), . . . , DL_((m+q)−1), DL_(m+q) are disposed onthe first insulating substrate 101. Each pixel includes one gate line GLof the n+p gate lines GL₁, . . . , GL_(n), GL_(n+1), . . . ,GL_((n+p)−1), GL_(n+p), one data line DL of the m+q data lines DL₁, . .. , DL_(m), DL_(m+1), . . . , DL_((m+q)−1), DL_(m+q), and one sub-dataline DL′ of the m′+q sub-data lines DL₁′, . . . , DL_(m)′, DL_(m+1)′, .. . , DL_((m+q)−1)′, DL_(m+q)′. In FIG. 15, for purposes of description,a pixel including the n-th gate line GL_(n), the m-th data line DL_(m),and the m-th sub-data line DL_(m)′ has been illustrated with the (n+1)thgate line GL_(n+1) of a next pixel adjacent to the pixel, butalternative exemplary embodiments are not limited thereto. In anexemplary embodiment, each pixel has substantially the same structureand function.

The n-th gate line GL_(n) extends along a first direction on the firstinsulating substrate 101. The m-th data line DL_(m), the m-th sub-dataline DL_(m)′, a first source electrode SE1, a first drain electrode DE1,a first sub-source electrode SE1′, a first sub-drain electrode DE1′, asecond sub-source electrode SE1″, a second sub-drain electrode DE1″, asecond source electrode SE2, a second drain electrode DE2, and a chargedividing electrode CDE are disposed on the first insulating substrate101 on which the n-th gate line GL_(n) is disposed.

A storage line CST is arranged substantially parallel to the n-th gateline GL_(n) and the (n+1)th gate line GL_(n+1), positioned between then-th gate line GL_(n) and the (n+1)th gate line GL_(n+1), and spacedapart from the n-th gate line GL_(n) and the (n+1)th gate line GL_(n+1).A portion of the storage line CST may branch therefrom along a seconddirection substantially perpendicular to the first direction. Thestorage line CST may be disposed in both areas of the transmissive areaTA and the reflective area RA.

The first source electrode SE1 and the first sub-source electrode SE1′branch from the m-th data line DL_(m) to partially overlap the n-th gateline GL_(n). The second source electrode SE2 branches from the m-thsub-data line DL_(m)′ to partially overlap the n-th gate line GL_(n).

The first drain electrode DE1 and the first sub-drain electrode DE1′ arespaced apart from the first source electrode SE1 and the firstsub-source electrode SE1′ to partially overlap the n-th gate lineGL_(n). The second drain electrode DE2 is spaced apart from the secondsource electrode SE2 to partially overlap the n-th gate line GL_(n).

A transmissive pixel electrode TE and a reflective pixel electrode REare disposed on the first source electrode SE1, the first sub-sourceelectrode SE1′ and the second source electrode SE2 and the first drainelectrode DE1, the first sub-drain electrode DE1′ and the second drainelectrode DE2, and a protective layer 120 is disposed therebetween. Thetransmissive pixel electrode TE is disposed in the transmissive area TA,includes a transparent conductive material, and the transmissive pixelelectrode TE further includes a first transmissive pixel electrode TE1and a second transmissive pixel electrode TE2 spaced apart from andinsulated from the first transmissive pixel electrode TE1. The firsttransmissive pixel electrode TE1 is connected to the first drainelectrode DE1 through a contact hole formed through the protective layer120. The second transmissive pixel electrode TE2 is connected to thefirst sub-drain electrode DE1′ through a contact hole formed in theprotective layer 120.

The second sub-source electrode SE1″ is connected to the secondtransmissive pixel electrode TE2 through a contact hole and partiallyoverlaps with the (n+1)th gate line GL_(n+1). The second sub-drainelectrode DE1″ is spaced apart from the second sub-source electrode SE1″to partially overlap the (n+1)th gate line GL_(n+1).

The charge dividing electrode CDE is connected to the second sub-drainelectrode DE1″ and partially overlaps the first transmissive pixelelectrode TE1 and the storage line CST. The charge dividing electrodeCDE forms a down-capacitor Cdown with the storage line CST with aninsulating layer 110 disposed therebetween, and forms an up-capacitorCup with the first transmissive pixel electrode TE1 with the insulatinglayer 110 disposed therebetween.

A second substrate 200 includes a second insulating substrate 201, and atransparent organic layer 220, a light-blocking layer 211, a colorfilter layer 210 and a common electrode CE are disposed on the secondinsulating substrate 201.

At least one dividing pattern is formed in at least one of the firsttransmissive pixel electrode TE1, the second transmissive pixelelectrode TE2, the reflective pixel electrode RE and the commonelectrode CE to divide the liquid crystal layer 300 into domains. Thedomains may be divided into the same area or different areas. Thedividing pattern is formed in at least one of the first transmissivepixel electrode TE1, the second transmissive pixel electrode TE2, thereflective pixel electrode RE and the common electrode CE, and thedividing pattern may have a slit shape (hereinafter referred to as aslit portion), an embossed shape (hereinafter referred to as an embossedportion), or a hole shape (hereinafter referred to as a hole portion).In an exemplary embodiment, a structure in which the slit portion isdisposed in the transmissive pixel electrode TE, has been shown and willbe described in further detail; however it will be noted thatalternative exemplary embodiments are not be limited thereto or thereby.For example, the slit portion may be formed in the reflective pixelelectrode RE or the common electrode, and the dividing pattern may bereplaced by an embossed portion or a hole portion.

In an exemplary embodiment, a portion of the n-th gate line GL_(n), thefirst source electrode SE1, and the first drain electrode DE1 form afirst thin film transistor T1. A portion of the n-th gate line GL_(n),the first sub-source electrode SE1′, and the first sub-drain electrodeDE1′ form a first sub-thin film transistor T1′. A portion of the (n+1)thgate line GL_(n+1), the second sub-source electrode SE1″, and the secondsub-drain electrode DE1″ form a second sub-thin film transistor T1″. Aportion of the n-th gate line GL_(n), the second source electrode SE2,and the second drain electrode DE2 form a second thin film transistorT2.

Referring to FIG. 15, when a gate signal is applied to the n-th gateline GL_(n), the first thin film transistor T1 and the second thin filmtransistor T2 are turned on in response to the gate signal to output afirst data signal and a second data signal, respectively. Then, thefirst data signal applied to the m-th data line DL_(m) is provided tothe transmissive pixel electrode TE through the first thin filmtransistor T1 and charged in the transmissive pixel electrode TE, andthe second data signal applied to the m-th sub-data line DL_(m)′ isprovided to the reflective pixel electrode RE through the second thinfilm transistor T2 and charged in the reflective pixel electrode RE.Since the m-th data line DL_(m) and the m-th sub-data line DL_(m)′ maytransmit different data signals, a first pixel voltage and a secondpixel voltage having different voltage levels may be applied to thetransmissive pixel electrode TE and the reflective pixel electrode RE,respectively.

When the gate signal is applied, the first thin film transistor T1 andthe first sub-thin film transistor T1′ are turned on in response to thegate signal to output the first data signal and a first sub-data signal,respectively. Accordingly, the first data signal and the first auxiliarydata signal are applied to the first transmissive pixel electrode TE1and the second transmissive pixel electrode TE2, respectively, and arethereafter charged into the first transmissive pixel electrode TE1 andthe second transmissive pixel electrode TE2, respectively. The signalsapplied to the first transmissive pixel electrode TE1 and the secondtransmissive pixel electrode TE2 are substantially identical, and thus afirst liquid crystal capacitor and a second liquid crystal capacitorcorresponding to the first transmissive pixel electrode TE1 and thesecond transmissive pixel electrode TE2, respectively, are charged witha first transmissive pixel voltage and a second transmissive pixelvoltage having the same voltage level.

The second sub-thin film transistor T1″ is turned on in response to agate signal applied to the (n+1)th gate line GL_(n+1) to output avoltage control signal after the gate signal is applied to the n-th gateline GL_(n). Thus, the second transmissive pixel electrode TE2 iselectrically connected to the charge dividing electrode CDE by thesecond sub-thin film transistor T1″. Then, the voltage levels of thefirst transmissive pixel voltage charged in the first liquid crystalcapacitor and the second transmissive pixel voltage charged in thesecond liquid crystal capacitor may be controlled by the up-capacitorCup and the down-capacitor Cdown. More particularly, the voltage levelof the first transmissive pixel voltage increases by the up-capacitorCup, and the voltage level of the second transmissive pixel voltagedecreases by the down-capacitor Cdown.

An increase and a decrease in the first and second transmissive pixelvoltages depend on capacitances of the up-capacitor Cup and thedown-capacitor Cdown. Therefore, different voltages may be applied tothe first transmissive pixel electrode TE1 and the second transmissivepixel electrode TE2 by forming a voltage controller.

As described herein, a signal cell gap LCD is achieved by dividing atransmissive pixel electrode TE into first and second transmissive pixelelectrodes TE1 and TE2, respectively, and applying different pixelvoltages to the first and second transmissive pixel electrodes TE1 andTE2. In addition, liquid crystal molecules may be aligned at differentangles from each other, to thereby substantially improve side visibilityand provide a wide viewing angle.

Thus, since the different pixel voltages are applied to the transmissivepixel electrode TE and the reflective pixel electrode RE, the liquidcrystal molecules included in the liquid crystal layer 300 correspondingto the transmissive area TA and the reflective area RA are controlled tohave different alignment angles from each other. As a result, a phaseretardation value of light traveling through the liquid crystal layer300 corresponding to the transmissive pixel electrode TE hassubstantially the same phase retardation value of light travelingthrough the liquid crystal layer 300 corresponding to the reflectivepixel electrode RE, and a gray-scale of the transmissive area TA isthereby matched with a gray-scale of the reflective area RA in an LCDwith a signal cell gap. In one or more exemplary embodiments, a nextgate line for the next pixel may be used instead of forming the sub-gatelines for corresponding pixels.

The present invention should not be construed as being limited to theexemplary embodiments set forth herein. Rather, these exemplaryembodiments are provided so that this disclosure will be thorough andcomplete and will fully convey the concept of the present invention tothose skilled in the art.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the art that various changes in form anddetails may be made therein without departing from the spirit or scopeof the present invention as defined by the following claims.

What is claimed is:
 1. A liquid crystal display comprising: a firstsubstrate including pixels, each of which includes a transmissive areaand a reflective area; a second substrate disposed opposite the firstsubstrate; and a liquid crystal layer disposed between the firstsubstrate and the second substrate, wherein each of the pixelscomprises: a first thin film transistor and a second thin filmtransistor which both output a data signal in response to a first gatesignal; a transmissive pixel electrode disposed in the transmissive areaand electrically connected to the first thin film transistor to charge afirst pixel voltage based on the data signal; a reflective pixelelectrode disposed in the reflective area and electrically connected tothe second thin film transistor to charge a second pixel voltage basedon the data signal; and a voltage controller which controls the firstpixel voltage and the second pixel voltage in response to a second gatesignal, wherein the voltage controller comprises: a third thin filmtransistor including a source electrode connected to a drain electrodeof the second thin film transistor or the reflective pixel electrode andwhich outputs a voltage control signal in response to the second gatesignal; a charge dividing electrode connected to a drain electrode ofthe third thin film transistor and which is charged with the voltagecontrol signal; and a storage line which overlaps at least a portion ofthe charge dividing electrode to form a first capacitor which controlsthe first pixel voltage and the second pixel voltage, wherein the secondgate signal is generated after the first gate signal, wherein thereflective pixel electrode comprises a concavo-convex portion, andwherein the concavo-convex portion comprises a base surfacesubstantially parallel to a surface of the first insulating substrateand a plurality of protrusions protruding from the base surface andbeing arranged on the base surface.
 2. The liquid crystal display ofclaim 1, wherein each protrusion has a first pitch in a first directionand a second pitch in a second direction different from the firstdirection and the first pitch is different from the second pitch.
 3. Theliquid crystal display of claim 1, wherein a surface of each protrusionhas a contact angle of about 10° or more with the base surface incross-section.
 4. The liquid crystal display of claim 1, wherein adistance from a point on the base surface corresponding to a highestpoint of each protrusion to one end of the each protrusion is differentfrom a distance from a point on the base surface corresponding to a thehighest point to the other end of the each protrusion.
 5. The liquidcrystal display of claim 1, wherein a cell gap of the transmissive areais greater than or equal to a cell gap of the reflective area.
 6. Theliquid crystal display of claim 1, further comprising: a first gate linewhich receives the first gate signal; a second gate line which receivesthe second gate signal; and a data line which receives the data signal.7. The liquid crystal display of claim 6, wherein the first gate line isconnected to a first pixel of the pixels, the second gate line isconnected to a second pixel, adjacent to the first pixel, of the pixels,and the voltage controller receives the second gate signal through thesecond gate line.
 8. The liquid crystal display of claim 1, wherein thesecond substrate comprises: a color filter layer; and a transparentorganic layer disposed in a first area of the color filter layer suchthat a thickness of the first area is less than a thickness of a secondarea, different from the first area, of the color filter layer.
 9. Theliquid crystal display of claim 1, wherein the second substratecomprises a color filter layer, and the color filter layer includes atleast one penetrating hole formed therethrough at an area correspondingto the reflective area of a corresponding pixel of the pixels.
 10. Theliquid crystal display of claim 9, wherein a cell gap of the area atwhich the penetrating hole is formed is greater than a cell gap ofanother area of the color filter layer.
 11. The liquid crystal displayof claim 1, wherein the second substrate comprises: a common electrodewhich forms an electric field with the transmissive pixel electrode andthe reflective pixel electrode; and at least one dividing patterndisposed on at least one of the transmissive pixel electrode, thereflective pixel area and the common electrode, wherein the at least onedividing pattern divides the liquid crystal layer into domains.
 12. Theliquid crystal display of claim 10, wherein the domains have differentareas.
 13. The liquid crystal display of claim 1, further comprising: afirst polarizer disposed on an outer surface of the first substrate; asecond polarizer disposed on an outer surface of the second substrate;and at least one phase retardation film disposed at least one of betweenthe first substrate and the first polarizer and between the secondsubstrate and the second polarizer.
 14. The liquid crystal display ofclaim 13, wherein at least one of the first polarizer, the secondpolarizer and the at least one phase retardation film comprises ananti-glare portion disposed thereon.